An assembly comprising a casing for a turbine engine, in particular for an aircraft, the turbine engine casing comprising an annular or cylindrical radially outer shell provided with a radially inner surface, and an aerodynamic treatment member comprising a plurality of grooves distributed in a circumferential direction, wherein the radially outer shell comprises a circumferential recess in which the aerodynamic treatment member is removably mounted, the treatment member extending along at least one angular sector and being complementary in shape to the circumferential recess, the treatment member comprising a circumferential opening into which the plurality of grooves opens.